Mimi Winsberg had completed dozens of marathons and triathalons, but four years ago, when she was in her late 30s, her health and athletic performance inexplicably declined. Doctors attributed it to aging, new motherhood, and chronic anemia, but no treatment worked, until Winsberg researched her symptoms online. She realized that she has celiac disease, a genetic auto-immune disorder caused by eating gluten protein. Doctors estimate that at least 1% of the population has the disease, but though it can be detected with inexpensive blood tests, only of a fraction of the cases are diagnosed. [The New York Times]